SLAM polynucleotides and polypeptides and uses thereof

Abstract

Novel methods for exporting target proteins from the cytosol to the extracellular surface of bacterial cells are provided. The methods are useful in that they permit the preparation of vaccines for the prevention of bacterial infectious diseases.

The invention claimed is: 
     
       1. A method of causing transport of a target protein from the cytosol to the extracellular surface of a host cell comprising the target protein, the method comprising:
 (a) providing a chimeric polynucleotide comprising as operably linked components:
 (i) a polynucleotide capable of controlling expression in the host cell; and 
 (ii) a polynucleotide encoding a Surface Lipoprotein Assembly Modulator (SLAM) polypeptide, wherein the polynucleotide comprises a polynucleotide sequence selected from the group consisting of SEQ.ID NO: 5; SEQ.ID NO: 199; SEQ.ID NO: 273; SEQ.ID NO: 385; SEQ.ID NO: 387; SEQ.ID NO: 1087; SEQ.ID NO: 1111; and SEQ.ID NO: 1181, ora polynucleotide sequence that encodes a polypeptide that is at least 90% identical to a polypeptide encoded by any of the foregoing polynucleotides; and 
 
 (b) introducing the chimeric polynucleotide in the host cell and growing the host cell to express and produce the SLAM polypeptide, thereby causing transport of the target protein from the cytosol to the extracellular surface of the host cell. 
 
     
     
       2. The method according to  claim 1  further comprising in step (b):
 providing a second chimeric polynucleotide comprising as operably linked components: 
 (i) a polynucleotide capable of controlling expression in the host cell; and 
 (ii) a polynucleotide encoding a target protein; and 
 further comprising a step (c) comprising: 
 introducing the first and second chimeric polynucleotide in the host cell and growing the host cell to produce the SLAM polypeptide and the target protein and cause transport of the target protein from the cytosol to the extracellular surface. 
 
     
     
       3. The method according to  claim 2 , wherein the target protein is an immunogen capable of eliciting an immune response in a host organism. 
     
     
       4. The method according to  claim 2 , wherein the target protein is an immunogenic polypeptide, or an immunogenic portion thereof, that is naturally displayed on the exterior surface of a pathogenic microorganism. 
     
     
       5. The method according to  claim 4 , wherein the pathogenic microorganism is selected from the group consisting of  Neisseria meningitidis, Neisseria gonorrhoeae, Neisseria lactamica, Neisseria cincera, Klebsiella denitrificans, Moraxella catarrhalis, Moraxella haemolytica, Actinobacillus pleuropneomoniae, Haemophilus somni, Haemophilus influenzae, Pasteurella multocida, Acinetobacter baumannii  or  Vibrio cholera.    
     
     
       6. The method according to  claim 4 , wherein the immunogen is a surface lipoprotein (SLP). 
     
     
       7. The method according to  claim 1 , wherein the target protein is a transferrin binding protein B (TbpB) comprising SEQ.ID NO: 1162 or a sequence that is at least 90% identical thereto. 
     
     
       8. The method according to  claim 1 , wherein the SLAM polypeptide is not naturally present in the host cell. 
     
     
       9. The method according to  claim 1 , wherein the target polypeptide is naturally present in the host cell. 
     
     
       10. The method according to  claim 1 , wherein the target polypeptide is not naturally present in the host cell. 
     
     
       11. The method according to  claim 2 , wherein the host cell is used to prepare a vaccine formulation. 
     
     
       12. The method of  claim 1 , wherein the polynucleotide comprises a polynucleotide sequence selected from the group consisting of SEQ.ID NO: 5; SEQ.ID NO: 199; SEQ.ID NO: 273; SEQ.ID NO: 385; SEQ.ID NO: 387; SEQ.ID NO: 1087; SEQ.ID NO: 1111; and SEQ.ID NO: 1181, or a polynucleotide sequence that encodes a Dohpeptide that is at least 95% identical to a polypeptide encoded by any of the foregoing polynucleotides. 
     
     
       13. The method of  claim 1 , wherein the polynucleotide comprises a polynucleotide sequence selected from the group consisting of SEQ.ID NO: 5; SEQ.ID NO: 199; SEQ.ID NO: 273; SEQ.ID NO: 385; SEQ.ID NO: 387; SEQ.ID NO: 1087; SEQ.ID NO: 1111; and SEQ.ID NO: 1181. 
     
     
       14. The method of  claim 7 , wherein the target protein comprises SEQ.ID NO: 1162 or a sequence that is at least 95% identical thereto. 
     
     
       15. The method of  claim 7 , wherein the target protein comprises polypeptide sequence SEQ.ID NO: 1162.